Andreas went through some “oops!” while reassembling his Ultimate keyboard after cleaning. He realized all keys are not the same shape – not talking about the space bar and return key here – but letters and numbers. Even though they have the same size, they don’t have the same angle of curvature. The angle of curvature makes fingers hit keys at the optimum angle of attack, limiting the impact pressure can have on the highly sensitive finger extremity. Fingers are fragile as some heavy Blackberry users know (Wired article: The Agony of ‘BlackBerry Thumb‘). That being said, Andreas shared his experience putting it all back together on his blog: